Treatment of hydrocarbon oil



sept. 2z, 1936.

G, w. MILLER TREATMENT OF HYDROCARBON yOIL Filed July 29, 1952 7, e NjIv l) www) A KW N w v @www wf m; H www. o we e J y ahw. 1m JW r Q 6 U/Patented Sept. 22, 1936 PATENT OFFICE y 2,055,085 TREATMENT or mRocARBoNon.

George W. Miller, Jackson Heights, N. Y., assignor to Universal OilProducts Company, Chicago, Ill., a corporation of South Dakota.

Application July 29, 1932, Serial No. 625,906'

6 Claims. (Cl. 196-51) This invention relates more particularly to animproved method and means of handling the polymer condensate resultingfrom the polymerization treatment of cracked hydrocarbon oil vaporsdirect from a cracking operation to increase the emcien'cy and yields ofthe cracking operation.

In the treatment of hydrocarbon oil vapors with polymerizing materialsuch as contact clays,

10 fullers earth and the like, a condensate containing the polymers isseparated from the treated vapors. This product is known in the industryand will be hereinafter referred to as polymer condensate. Thepolymerization treatment of light vaporous products direct from thefractionator of a hydrocarbon oil cracking process. has recently comeinto commercial prominence and it has been proposed to dispose of thepolymer condensate resulting from such treatment by returning it to theheating coil of the cracking system together with raw oil charging stockand reux condensate from the fractionator of the cracking system for thepurpose of increasing the yields of desirable light products.

It has been found that this method of handling the polymer condensatemay result in the accumulation of excessive quantities of coke orcarbonaceous material in the heating coil, due to the inability of theheavy polymers to withstand thel conversion conditions required for thetreatment of the other materials (raw oil and reflux condensate)supplied to the same heating coil without excessive cracking of theheavy polymers and the resulting formation therefrom of high yields ofcoke and gas. This, of course, is true regardless of whether thepolymers are returnedvdirect to the heating coil or to the fractionatorof the cracking system, as in the latter case the heavy polymers areeventually supplied to the heating coil together with re'ux condensatefrom the fractionator.

In cracking processes of the character wherein residual oil from thereaction chamber of the cracking system, alone or together with vaporousproducts from the same reaction zone, is subjected to furthervaporization at reduced pressure, it has been attempted to overcomecoking difficulties in the heating coil of the system by returning thepolymer condensate to said reduced pressure chamber. It has been found,however, that the mild conditions existing in this reduced pressure zonedo not effect sufficient further conversion of the polymer condensate. lThe present invention obviates the diiliculties formerly encountered inthe return of polymer tions, containing the heavy coke-forming polymers,from the system, alone or together with re- 5 sidual liquid conversionproducts produced by the cracking operation, and returning the lowerboiling fractions, which are substantially free of coke-formingpolymers, for further conversion by supplying them either to thefractionator or 10 direct to the heating coil of the cracking system.

As a` further special feature of the present invention, when utilized inconjuncton with that type of cracking system wherein residual liquidconversion products or both vaporousand resid- 15 ual liquid conversionproducts are withdrawn through a common outlet from a high pressurereaction chamber to further vaporization in a zone of reduced pressure,all or a portion of the low boiling fractions of the polymer condensate20 may be blended with the conversion products passing from the reactionchamber to the reduced pressure vaporizing chamber, serving as a diluentand cooling medium and being subsequently vaporized in the vaporizingchamber, passed to 25 the fractionator of the cracking system, condensedtherein together with the reux condensate and returned therewith to theheating coil for further conversion.

Any distillate within the boiling range of the 30 desired final motorfuel product of the system contained in the low boiling fraction -of thepolymer condensate will, of course, pass overhead with the vapors fromthe fractionator to further polymerization treatment, condensation andcol- 35 lection when said low boiling fraction of the polymer condensateis returned to the fractionator or to the vaporizing chamber. On theother hand, when this fraction is returned direct tothe' heating coilits components of motor fuel boiling 40 range may be subjected tofurther conversion in the cracking zone of the system whereby theiranti-knock value may be improved, particularly when relatively severeconversion conditions are utilized in the heating coil. 45

The accompanying diagrammatic drawing illustrates one specific form ofapparatus for carrying out the invention. It should be understood,however, that the features of the invention may be applied to any typeof cracking 50 system and are not limited to the one here illustratedand described, nor are they limited to the particular form of apparatusshown in conjunction with the cracking system.

Referring to the drawing, raw oil charging 2 a stock for the crackingsystem is supplied through line I and valve 2 to pump 3 from which itmay be fed through line 4, valve 5 and line 6 direct to heating coil 1or through line 8 and valve 9 into fractionator I0, to be preheatedtherein by direct contact with the ascending vapors in this zone,assisting their fractionation and passing, together with the refluxcondensate separated from the vapors in the fractionator, through lineII and valve I2 to pump I3 from which the reflux condensate, or reuxcondensate and preheated raw oil, is supplied through line 6 and valveI4 to heating coil 1. The raw oil may, of course, be preheated, all orin part, by any other well known means (not shown) prior to itsintroduction into the heating coil.

The oil supplied to heating coil 1 is heated to the desired conversiontemperature preferably at substantial superatmospheric pressure by meansof heat supplied from a furnace I5 of any suitable form and the heatedoil is discharged from the heating coil through line I6 and valve I1into reaction chamber I8, which is also preferably maintained atsubstantial superatmospheric pressure.

Reaction chamber I8 preferably is heavily insulated or may, whendesired, be externally heated, although insulation and heating means arenot shown in the drawing, to prevent the excessive loss of heat throughthe walls of the chamber by radiation so that the heated oil introducedinto this zone, and particularly the Vaporous conversion products, aresubjected to continued conversion, during their passage through thereaction chamber.

In the particular form of cracking system here illustrated, bothVaporous and residual liquid conversion products are withdrawn from thelower portion of the reaction chamber in commingled state through lineI9 and valve 20 and are introduced into a vaporizing chamber 2| which ispreferably maintained at substantially reduced pressure relative to thatemployed in chamber I8 .by means of which further vaporization of theresidual liquid withdrawn from' chamber I8 is eiected. Residual liquidremaining unvaporized in chamber 2| may be withdrawn there. om tocooling and storage or to any desired'vfurther treatment through line 22and valve 23 or, when desired, conditions may be so controlled inchamber 22 that substantially no liquid residue is produced,the'residual products of the system being reduced to coke in this zone,in which case the coke may be allowed to accumulate within chamber 2|tobe removed therefrom after lits operation is completed. A plurality ofcoking chambers similar to chamberv 2|, but not illustrated in thedrawing, may be employed, when desired, and may be operated eitheralternately or simultaneously to provide additional space for theaccumulation of coke and permit prolonged operation of the process.

Vaporous products are withdrawn from chamber 2| through line 24 andvalve 25 to fractionation in frationator I0 wherein their insuilcientlyconverted heavy components are condensed as reflux condensate to bereturned, as already described, to heating coil 1 for furtherconversion. Vaporous products of the 'desired end-boiling point,remaining uncondensed in fractionator I8, are withdrawn from its upperportion through line 26 and may pass through line 21 and valve 28 intopolymer treating chamber 29 or through line 21 and valve 28' intopolymer treating chamber 29'.

'Ihe treating chambers 29 and 29' are similar- 30', controlled by therespective valves 3| and` 3|'. When the polymer treating chambers areoperated in series the vapors from fractionator 29 may, for example,enter chamber 29 through line 21 and valve 28, the polymers formed beingseparated in the lower portion of this chamber and the vapors passingthrough line 32 and valve 33 into the upper portion of chamber1 29', inwhich case the treated vapors and polymers formed in chamber 29' may beWithdrawn through line 30' and valve 3| and commingled in line 34 withpolymers withdrawn from the lower portion of chamber 29 through line 30and valve 3|.

The treated vapors and polymerization products from chambers 29 and 29'pass through line 34 into distilling and fractionating column 35 whereinthe polymers are subjected to reheating and vaporization and the vaporsare fractionated for the removal of polymerization products therefrom.Treated/vapors of the desired end-boiling point, substantially freed ofpolymerization products ,by fractionation, are withdrawn from the upperportion of the fractionator through line 36 andvalve 31, are subjectedto condensation and cooling in condenser 38, from which the resultingdistillate and uncondensable gas is withdrawn through line 39 and valve40 to collection in receiver 4I. Uncondensable gas `may be released fromthe receiver through line 42 and valve 43. Distillate may be withdrawnfrom receiver 4I through line 44 and valve 45. A portion of thedistillate collecting in receiver 4| may, when desired, be recirculated,by well known means (not shown) to either or both fractionators of thesystem to assist fractionation and to maintain the desired vapor loutlettemperature from each of these zones. Well known means (not shown) mayalso be provided for returning a portion of this product to chambers 29and 29' into which it may be sprayed as a washing medium to washpolymerization products from and revive the treating material.

A heating or reboiling coil '46 may be provided in the lower portion ofdistilling and fractionatingcolumn through which any suitable heatingmedium such as steam or hot Vaporous or liquid products of the processare passed for the purpose of reboiling the polymer condensate whichcollects in this zone and vaporizing all but its heavy components ofhigh coke-forming characteristics.

The vheavy polymers remaining unvaporized l uct of thesystem. Blendingof the polymers and cracked residue to form a single `heavy liquidproduct is, of course, only practiced when chamber 2| is operated forthe production of liquid residue. When coking of the residual conversionproducts is employed in chamber 2| the` heavy polymers may pass throughvalve 53, in line 52, into chamber 2| wherein they may also besubjectedto coking.

The treated vapors entering column from chambers 29 and 29' passtogether with the light fractions of the polymer condensate vaporized,as already described, in the lowerportion of column 35, into the upperor fractionating portion of the column which is separated from the loweror reboiling section by a suitable partition or tray 54. Vaporizedfractions of the polymer condensate, not suitable as a portion of thefinal light distillate product of the system but lighter than the highcoke-forming polymers remaining unvaporized in the lower section ofcolumn 35, are condensed by fractionation in the upper section of thecolumn and collect as light polymer condensate above the tray orpartition 54, to be withdrawn therefrom through line 55 and valve 56 topump 51, by means of which it is returned to the cracking system forfurther conversion in any one or any combination of several manners. Allor any 'portion of the light polymer condensate may pass from pump 51through line 58, valve 59 and line 6 direct to heating coil 1, or may bediverted from line 58 through line 60 andvalve 6I into fractionator I8wherein they may serve as a cooling means to assist fractionation of thevapors, passing therefrom, together with reflux condensate, to heatingcoil 1 for further conversion.

As a special feature of thefinvention, a portion or all of the lightpolymer condensate may be blended with the stream of conversion productspassing fromchamber I8 to chamber 2|, serving as a diluent and coolingmedium to assist in preventing excessive conversion and the formation ofcoke in the lower portion of chamber I8 and in line I9. The lightpolymer condensate used for this purpose may be blended, all or in part,with the conversion products in the lower portion of chamber I8 bypassing it through line 62 and valve 63 into the lower portion of thereaction chamber or may be blended, all or in part, with the materialpassing from chamber lII! to chamber 2| through line I9 by passing itthrough line 64 and valve 65 into line I9 or any other well known meansmaybe employed, although notillustrated in the drawing, such as, forexample, spraying the polymer condensate against the walls of reactionchamber' ltor fuel product of the system, will be condensed infractionator II) and returned therefrom to.

heating coil 1 for further more severe conversion. At the same time anyheavy residual products resulting from conversion of the polymercondensate, blended with the conversion products from chamber I8,separate from the lighter conversion products in chamber 2| and blendwith the otherresidualconversion products of the system to be withdrawnas residual liquid from chamber 2| or reduced to coke in this zone.

`It will be evident to one skilled in the art that many modifications ofthe specific form of apparatus illustrated( and above described may beemployed without departing from the scope of the invention. For example,treated vapors and polymer condensate may be separately Awithdrawn fromthe treating chambers inthe usual manner instead of. being withdrawn incommingled state. The treated vapors may then be subjected! tofractionation for the removal of` additional polymer condensate andi allof the polymer condensate may be collected, subjected to redistillationor reboiling and fractionation for separation into light and heavyfractions,

which fractions may then be handled in the' manned prescribed. It istherefore not intended to limit the invention to any specific form ofapparatus, the main feature of the invention being the separation by anymeans of light and heavy fractions of the polymer condensate and thereturn of only the light fractions to further conversion in the heatingcoil of the same cracking system, wherein the vapors subjected topolymerization treatment are produced.

Inasmuch as the features -of the present invention are adaptable tonearly any type of cracking system any desired conversion conditions maybe employed, however, in the particular type of system here illustratedand above described, conversion temperatures ranging from 875 to 975 F.with a superatmospheric pressure of from 100 to 800 pounds, orthereabouts, per square inch are preferably employed at the outlet fromthe heating coil. A superatmospheri'c pressure within substantially thissame range is preferred inthe reaction chamber and the pressure ispreferably reduced in' the vaporizing chamber and in succeeding portionsof the cracking system, said reduced pressure ranging, for example, from100 pounds, or thereabouts, per square inch down to substantiallyatmospheric pressure. When desired, reduced pressure may be employedinthe distilling and fractionating column to which the polymercondensate is supplied, relative to that in the treating chambers, toassist vaporization of the polymer condensate. The exact conditionsemployed in the distilling and fractionating column will vary withdifferent charging stocks and different operating conditions in thecracking portion of the system. Preferably, however, reboiling andfractionation are so controlled in this zone that that fraction of thepolymer condensate returned to the fractionator or direct to the heatingcoil of the vcracling system for further conversion has an end-boilingpoint no higher than the end-boiling point of the combined feed (raw oiland reflux condensate from the fractionator of the crackingsystem) whichis supplied to the same heating coil and the vaporous product withdrawnfrom thel upper portion of this column has an end-boiling pointcorresponding to the desired end-boiling'point of the nal lightdistillate product of the system. For example, with the distillingfractionating column operated at substantially `atmospheric pressure,the polymers may be' reheated in the lower portion of this column to atemperatureranging from 500 to 700 F., or thereabouts, and. the vaporousproducts may be withdrawn from the upper portion of the column at atemperature of 350 to 437 F.,

or thereabouts.

I claim as my invention:

1. In a process for the treatment of hydrocarbon oil wherein an oil issubjected to conversion temperature at superatmospheric pressure in aheating coil and communicating enlarged reaction chamber, liquid andvaporous conversion products are withdrawn from the reaction chamber toa reduced pressure vaporizing chamber, unvaporized residual liquid iswithdrawn from the vaporizing chamber, vaporous products from thevaporizing chamber are subjected to fractionation, the heavy componentsof the vapors, condensed by fractionation, are returned to the heatingcoil for further conversion and fractionated vaporous products of thedesired end-boiling point are subjected to refining by polymerizationtreatment, whereby polymer condensate containing gum and color-formingcompounds and also containing desirable light components is form'ed, theimprovement which comprises subjecting said polymer condensate tofurther heating for the removal therefrom of desirable light componentsand separation of the remaining portion into light and heavy fractions,withdrawing said heavy fractions from the system and returning said lastmentioned light fractions, Without prior heating thereof to crackingtemperature, to the reaction chamber for further conversion.

2. In a process for the treatment of hydrocarbon oil wherein an oil issubjected to conversion temperature at superatmospheric pressure in aheating coil and communicating enlarged reaction chamber, liquid andvaporous conversion products are withdrawn from the reaction chamber toa reduced pressure vaporizing chamber,un vaporized residual liquid iswithdrawn, from the vaporizing chamber, vaporous products from thevaporizing chamber are subjected to fractionation, the heavycomponents-of the vapors, condensed by fractionation, are returned tothe heating coil for further conversion and fractionated vaporousproducts of the desired end boiling point are subjected to refining bypolymerization treatment with fullers earth whereby polymer condensatecontaining gum and color-forming compounds and also containing desirablelight components is formed, the improvement which comprisessubjectingsaid polymer condensate to further heating for the removaltherefrom of desirable light components and separation of the remainingportion into light and heavy fractions, withdrawing said heavy fractionsfrom the system and returning said last mentioned light fractions,without prior heating thereof to crackingtemperature, to the reactionchamber for further conversion.

3. In a process for the treatment of hydrocarbon oil wherein an oil issubjected to conversion temperature at superatmospheric pressure in aheating coil and communicating enlarged reaction chamber, liquid andvaporous 'conversionv products are withdrawn from the reactionchamcomponents is formed, the improvement which comprises subjectingsaid polymer condensate to further heating for the removal therefrom ofdesirable light compenents and separation of the remaining portion intolight and heavy fractions, withdrawing said heavy fractions from thesystern and returning said last mentioned light fractions, without priorheating thereof to cracking temperature, to the reaction chamber forfurther conversion. c

4. In a process for the treatment of hydrocarbon oil wherein an oil issubjected to conversion temperature at superatm'ospheric pressure in aheating coil and cbmmunicating enlarged reaction chamber, liquid andvaporous conversion products are lwithdrawn from the reaction chamber toa zone of reduced pressure, vaporous products are withdrawn from thereduced pressure zone and subjected to fractionation, the heavycomponents of the vapors, condensed by fractionation, are returned tothe heating coil for further conversion and fractionated vaporousproducts of the desired end-boiling point are subjected to rening bypolymerization treatment, whereby polymer condensate containing gum andcolor-forming compounds and also `containing desirable light componentsis formed, the improvement which comprises subjecting said polymercondensate to further heating and fractionation for the removaltherefrom of desirable light components, and separation of the remainingportion into light and heavy fractions and returning said lightfractions,

without prior heating thereof to cracking temperature, to the reactionchamber of the cracking system for further conversion.

5. In a hydrocarbon oil cracking process of the character wherein theoil is heated to cracking temperature under pressure while owing in a.restricted stream through a. heating zone and thence discharged into anenlarged reaction zone maintained under cracking conditions oftemperature and pressure wherein further conversion of the oil occurs,the method which comprises subjecting the gasoline vapors produced bythe cracking to a polymerization treatment thereby forming polymercondensate, separating the latter into a light fraction and a heavyfraction, introducing at least a portion of said light fractionwithoutprior heating thereof to cracking `temperature, into the reaction zoneand commingling the same therein with the heated oil discharged from theheating zone, and Withdrawing said heavy fraction from the system.

6. A conversion process which comprises sub- -jecting hydrocarbon oil ina cracking zone to cracking temperature under suicient superatmosphericpressure to maintain a substantial portion thereof in liquid phase,removing both vapors and unvaporized oil as a mixture from the crackingzoneand discharging the same into a flashing zone maintained under lowerpressure than the cracking zone, separating said mixture into vapors andresidue in the flashing zone, fractionating the vapors to condensefractions thereof heavier than gasoline, subjecting the uncondensedgasoline vapors to a polymerization treatment, thereby forming polymercondensate, separating the latter into a light fraction and aheavyfraction, returning the light fraction to the cracking zone for crackingtreatment therein and introducing said heavy fraction directly, andwithout prior cracking treatment thereof, to the flashing Zone.'

GEORGE W. MILLER.

.CERTIFICATE 0F coRREcTIoN.

Patent No. 2,/O55,085. September 22, 1936.

GEORGE W. MILLER.l

It is hereby certified that the above numbered patent was erroneouslyissued to "Universal Oil Products Company, of Chicago, Illinois, acorporation of South Dakota", whereas said patent should have beenissued to Universal O11 Products Company, of Chicago, Illinois, acorporation of Delaware, as assig nee vby mesne assignments, as shown bythe records of assignments in this offce; and that the said LettersPatent should be read with this correction therein that the same mayconform to the record of the case in the Patent Office.

Signed and sealed this 17th day of November, A. D. 1956 Henry VanArsdale (Seal) Acting Commissioner of Patents.

